The invention relates to an apparatus adapted to be mounted in an opening in a mounting wall; and more particularly to an apparatus which is secured by a mounting spring which is mounted on a wall of the apparatus and which flexes in a direction transverse to the direction in which the apparatus is inserted in the opening, so as to clamp the mounting wall between a shoulder on the spring and the flange on the apparatus.
A known apparatus of the above kind (see German patent application No. 2,360,600) uses a mounting spring which is molded in one piece with a front panel. The panel is secured to the apparatus by threaded sleeves and nuts. The shoulder of the mounting spring is wedged against a part of the mounting wall by an abutment surface on a mounting plate. A disadvantage of such an apparatus is that, with thicknesses of mounting walls which differ greatly in practice, the same apparatus is mounted with differing securing forces or clamping forces. Moreover, a separate mounting plate is required.
Another form of mounting is shown in European Patent Application 0073073, to which U.S. patent application Ser. No. 644,667 now Pat. No. 4,524,933 corresponds. In that arrangement a bifurcate mounting spring is fixedly secured to a side wall of an apparatus. The apparatus is secured in a mounting wall by means of a shell. Adaptation to the different thicknesses of mounting walls is obtained by the flexibility of tongues formed in the shell.